Ceramic inkjet ink for red decoration

ABSTRACT

Disclosed are compositions, such as inkjet inks, for jetting onto a ceramic substrate, and associated methods and systems. The compositions comprise a pigment compound that is configured to be jetted on a ceramic substrate during a ceramic inkjet process to impart a color effect to the ceramic substrate, and a reduction agent which, when exposed to a firing temperature, reacts with the pigment compound to cause a reduction reaction. In some embodiments, the pigment compound comprises jettable copper particles, which can cause the fired composition to take on a red or oxblood color, which can be used for decoration.

FIELD OF THE INVENTION

At least one embodiment of the present invention pertains to compositions that produce a reduction reaction, which impart a color effect to a ceramic substrate when exposed to a firing temperature.

BACKGROUND

In ceramic inkjet printing processes, traditional inorganic ceramic glazes and/or stains can produce stable red shades at higher temperatures, from zircon-encapsulated cadmium selenide (CdSe) pigments, which are commonly referred to as cadmium red.

However, inkjet ink pigments require smaller particle sizes than traditional ceramic stains and therefore usually include a pigment milling step in the manufacturing process. This milling step compromises the protective encapsulation layer used with CdSe pigments, and leaves the pigment vulnerable to degradation and color loss. CdSe pigments are not useable in ceramic inkjet inks at this time.

In the field of inkjet ceramics, options for red shade colors at porcelain firing conditions are not known to exist at this time.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the present invention are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements.

FIG. 1 illustrates an embodiment of an enhanced composition that is jetted onto a ceramic substrate, wherein the enhanced composition comprises a pigment compound and a reduction agent.

FIG. 2 is a schematic block diagram of an enhanced composition on a ceramic substrate, wherein the workpiece is exposed to a firing temperature, and wherein the reduction agent reacts with the pigment compound to cause a reduction reaction.

FIG. 3 is a schematic diagram of a printing environment for jetting a composition onto a ceramic workpiece, wherein the composition comprises a pigment compound and a reduction agent.

FIG. 4 is a schematic diagram of a system for heating a ceramic workpiece having a jetted composition, wherein when exposed to the heat, the reduction agent and the pigment compound react to cause a reduction reaction.

FIG. 5 is a flowchart of a method for producing an enhanced ceramic workpiece.

FIG. 6 illustrates an embodiment of an enhanced composition on a ceramic substrate, comprising a reduction agent jetted onto the ceramic substrate, and a pigment compound jetted onto the reduction agent.

FIG. 7 shows an embodiment of an enhanced composition on a ceramic substrate, comprising a pigment compound jetted onto the ceramic substrate, and a reduction agent jetted onto the pigment compound.

FIG. 8 illustrates an alternate embodiment of an enhanced composition on a ceramic substrate, which can include one or more jetted layers below and/or above the composition.

FIG. 9 is a schematic block diagram of components that can be included in some embodiments of the enhanced composition.

FIG. 10 is a flowchart of a method for manufacturing a jettable composition.

FIG. 11 is a high-level block diagram showing an example of a processing device that can represent any of the systems described herein.

DETAILED DESCRIPTION

References in this description to “an embodiment”, “one embodiment”, or the like, mean that the particular feature, function, structure or characteristic being described is included in at least one embodiment of the present invention. Occurrences of such phrases in this specification do not necessarily all refer to the same embodiment. On the other hand, the embodiments referred to also are not necessarily mutually exclusive.

Introduced here is a technique that enhances or extends an available color gamut for inkjet ceramics to provide, for example, red shade color options at porcelain firing conditions.

In certain embodiments, the technique introduced here involves the following sequence of actions, as described more fully below. Initially, an enhanced composition is jetted onto a ceramic substrate (also called a “workpiece”), e.g., a ceramic tile. The composition comprises a pigment compound, and a corresponding reduction agent, which are configured to be jetted, either together or separately, onto a ceramic workpiece. In some embodiments, the pigment compound comprises particles of a copper component, wherein the pigments are sized, e.g., by milling, to be jetted through an inkjet system. The reduction agent is configured to react with the pigment compound during the firing of the ceramic workpiece.

In some embodiments, the enhanced composition can expand the available color gamut, as compared to prior jettable compositions, such as to produce a red component, e.g., oxblood red, either alone or combined with other color components.

FIG. 1 illustrates an embodiment 100 of an enhanced composition 106, e.g., an inkjet ink, on a ceramic substrate 104, wherein the enhanced composition 106 comprises a pigment compound 108 and a reduction agent 110. The composition 106 can be jetted 314 (FIG. 3), 502 (FIG. 5) onto the ceramic substrate 104, such as by one or more print heads 306. The composition 106 shown in FIG. 1 can comprise one or more jetted layers 106,602,604 (FIG. 6, FIG. 7). The ceramic workpiece 102 is subsequently fired (e.g., in a kiln), causing a reduction reaction 204 between the pigment compound 108 and the reduction agent 110.

While the workpiece 104 is generally described herein as a ceramic substrate 104, it should be understood that the technique introduced here can be suitably adapted for a wide variety of workpieces that can be fired, e.g., tiles, such as ceramics, which can be manufactured from clay, minerals and water, or porcelain, which can be manufactured from finely ground sand.

In some embodiments, the pigment component 108 includes particles of a copper component, such as comprising any of CuO, CuCO₃, or CuS0₄. The size of the particles is configured to be jetted 314 (FIG. 3), such as within a carrier 902 (FIG. 9). For example, in an embodiment, the pigment particles are milled to an average particle size of 1 micron or less. In some embodiments, the copper particles cause the enhanced composition 106 to take on a red color, e.g., having a characteristic wavelength of 620-740 nm, upon firing 504 (FIG. 5). In some embodiments, the copper particles cause the enhanced composition 106 to take on a violet, burgundy, or oxblood color, e.g., having a characteristic wavelength of 380-440 nm, upon firing 504.

In an embodiment of the composition 106, the reduction agent 110 is configured to produce a reduction reaction with the pigment component 108, when fired on the ceramic substrate 104. For instance, for a pigment component 108 comprising a copper component, as discussed above, the reduction agent 110 may preferably comprise any of SiO, SiC, SiN, or BN.

In one example, an oxblood red color results from the reduction of Cu²⁺ to Cu⁺/Cu⁰. Since SiO₂ is a primary component in glaze formulations, the SiO₂ produced during the reduction of the copper pigment component 108 is incorporated into the resultant glaze 206 (FIG. 2), upon the application of sufficient heat. An example is shown in Equation (1)

4CuO(Black)+Si→2Cu₂O_((Red))+SiO₂.  (1)

FIG. 2 is a schematic block diagram 200 of an enhanced composition 104 (FIG. 1) on a ceramic substrate 102, wherein the workpiece 102 is exposed to a firing temperature 202, and wherein the reduction agent 110 reacts with the pigment compound 108 to cause a reduction reaction 204. The substrate 104 may comprise a variety of ceramics 104 that can be fired in any temperature range that corresponds to the reduction reaction 204. In some embodiments of the enhanced composition 106 wherein the pigment component 108 includes copper, the firing temperature 202, when controlled within a kiln 404 (FIG. 4) has a range of 1050 degrees C. to 1300 degrees C. The jetted composition 106 on the workpiece 102 forms a glaze 206 as a result of the firing 504 (FIG. 5), whereby the color of the resultant glaze 206 takes on a color due to the reduction reaction 204 between the pigment compound 108 and the reduction agent 110. The specific resultant color can also depend on specific operational parameters, e.g., specific temperatures, firing schedules, temperature ramping, down-firing, etc., and/or the use of one or more additional constituents in the composition 106, such as other pigments 906 (FIG. 9), dyes 908 (FIG. 9), and/or other additives, dispersions, or particles 910 (FIG. 9).

FIG. 3 is a schematic diagram 300 of an illustrative printing system 302 for jetting 314 a composition 106 onto a ceramic workpiece 104, wherein the composition 106 comprises a pigment compound 108 and a reduction agent 110. The printing system 302 seen in FIG. 3 includes a print head assembly 304, comprising one or more print heads 306 having corresponding jets 312. A supply module 308 is connected to the print heads 306, whereby the composition is transferred to the print heads 306, for jetting 314 onto a ceramic substrate 104, as controlled by a print controller 310.

FIG. 4 is a schematic diagram 400 of a firing system 402 for heating a ceramic workpiece 102 having a jetted composition 104 (FIG. 3), wherein when exposed to sufficient heat, the reduction agent 110 and the pigment compound 108 react to cause a reduction reaction 204. The firing system 402 seen in FIG. 4 includes a kiln 404 having an interior 406 defined therein, and a heating system 410, under the control of, e.g., a firing controller 408, wherein the heating system 410 comprises a heat source and can additionally comprise a mechanism for air circulation, e.g., a fan. The firing system 402 is operable to heat the jetted substrate 102 to a firing temperature 202 in a temperature range from 1050 degrees C. to 1300 degrees C., to cause a reduction reaction 204 between the pigment compound 108 and the reduction agent 110. The jetted composition 106 on the workpiece 102 forms a glaze 206 as a result of the firing, while the color of the resultant glaze 206 takes on a color due to the reduction reaction 204 between the pigment compound 108 and the reduction agent 110.

FIG. 5 is a flowchart of a method 500 for producing an enhanced ceramic, which comprises jetting 502 a composition 106 onto a ceramic substrate, i.e., a workpiece 104, wherein the composition 106 comprises a pigment compound 108 and a reduction agent 110, and heating 504 the composition to a temperature at which a reduction reaction 204 occurs between the reduction agent 110 and the pigment compound 108, causing a color effect to be produced on the ceramic substrate 104.

In some embodiments of the technique introduced here, the pigment compound 108 and the reduction agent 110 can be supplied in a single composition 106, such as within an appropriate jettable carrier 902 (FIG. 9), e.g., water, whereby the pigment compound 108 and the reduction agent 110 are jetted 502 concurrently onto the ceramic substrate 104. However, other embodiments of the technique allow separate jetting of the pigment compound 108 and the reduction agent 110, as long as the pigment compound 108 and the reduction agent 110 come into contact with each other during the heating 504, to initiate the reduction reaction 204 between the reduction agent 110 and the pigment compound 108.

For example, FIG. 6 illustrates an embodiment 600 of an enhanced composition 106 on a ceramic substrate 104, wherein the enhanced composition 106 comprises a layer 602 of reduction agent 110 that is jetted 502 onto the ceramic substrate 104, and a layer 604 of pigment compound 108 that is jetted 502 onto the layer 602 of reduction agent 110.

As another example, FIG. 7 shows an embodiment 700 of an enhanced composition 106 on a ceramic substrate 104, wherein the enhanced composition 106 comprises a layer 604 of pigment compound 108 that is jetted 502 onto the ceramic substrate 104, and a layer 602 of reduction agent 110 that is jetted 502 onto the jetted layer 604 of pigment compound 108.

FIG. 8 illustrates an alternative embodiment 800 of an enhanced composition 106 on a ceramic substrate 104, which can include one or more jetted layers below 802 and/or above 804 the composition 106. For example, a jetted lower layer 802 can comprise any of a primer, a basecoat, and/or one or more jetted colors. Similarly, a jetted upper layer 804 may comprise one or more jetted clear, translucent or opaque color layers over at least a portion of the jetted composition 106.

FIG. 9 is a schematic block diagram 900 of components that can be included in some embodiments of the enhanced composition 106. As discussed above, the pigment compound 108 and the reduction agent 110 can be supplied as a single composition 106 with, e.g., an appropriate carrier 902. The combined composition 106 can further comprise, for example, any of additional colorants 904, e.g., other pigments 906 and/or dyes 908, or other constituents 910, such as additives, dispersions, and/or jettable particles.

As also discussed above, some embodiments of the technique allow for separate jetting of the pigment compound 108 and the reduction agent 110, whereby each of the pigment compound 108 and the reduction agent 110 are supplied as jettable compositions, e.g., each within a corresponding carrier 902. One or both of the pigment compound 108 and the reduction agent 110 can further comprise any of additional colorants 904, e.g., other pigments 906 and/or dyes 908, or other constituents 910, such as additives, dispersions, and/or jettable particles.

FIG. 10 is a flowchart of a method 1000 for manufacturing an enhanced composition 106 for jetting 502 onto a ceramic substrate 104. As shown in FIG. 10, the manufacturing 1002 can comprise adding 1004 a jettable pigment compound 108 to a carrier 902, such as water. As discussed above, the pigment compound 108 can comprise particles, e.g., copper, having an average particle size of, for example, less than 1 micron (to allow jetting), whereby the particles can be milled or polished to achieve a desired size. The manufacturing method 1000 seen in FIG. 10 also comprises adding 1006 a jettable reduction agent 110 to a carrier 902, which can be a separate carrier 902, such as for independent jetting 502 of layers 602,604 (FIG. 6, FIG. 7). In some embodiments, the jettable reduction agent 110 is added to the same carrier 902 as that used for the jettable pigment compound 108, such as for concurrent jetting 502. Once prepared, the enhanced composition 106, comprising either a single composition 106, or separate jettable components 108, 110, is typically provided for use by the printing system 302 (FIG. 3).

FIG. 11 is a high-level block diagram showing an example of a processing device 1100 that can be a part of any of the systems described above, such as the print controller 310, the firing controller 408, or a system for manufacturing the enhanced compound 106. Any of these systems may be or include two or more processing devices such as represented in FIG. 11, which may be coupled to each other via a network or multiple networks.

In the illustrated embodiment, the processing system 1100 includes one or more processors 1102, memory 1104, a communication device 1106, and one or more input/output (I/O) devices 1108, all coupled to each other through an interconnect 1110. The interconnect 1110 may be or include one or more conductive traces, buses, point-to-point connections, controllers, adapters and/or other conventional connection devices. The processor(s) 1102 may be or include, for example, one or more general-purpose programmable microprocessors, microcontrollers, application specific integrated circuits (ASICs), programmable gate arrays, or the like, or a combination of such devices. The processor(s) 1102 control the overall operation of the processing device 1100. Memory 1104 may be or include one or more physical storage devices, which may be in the form of random access memory (RAM), read-only memory (ROM) (which may be erasable and programmable), flash memory, miniature hard disk drive, or other suitable type of storage device, or a combination of such devices. Memory 1104 may store data and instructions that configure the processor(s) 1102 to execute operations in accordance with the techniques described above. The communication device 1106 may be or include, for example, an Ethernet adapter, cable modem, Wi-Fi adapter, cellular transceiver, Bluetooth transceiver, or the like, or a combination thereof. Depending on the specific nature and purpose of the processing device 1100, the I/O devices 1108 can include devices such as a display (which may be a touch screen display), audio speaker, keyboard, mouse or other pointing device, microphone, camera, etc.

Unless contrary to physical possibility, it is envisioned that (i) the methods/steps described above may be performed in any sequence and/or in any combination, and that (ii) the components of respective embodiments may be combined in any manner.

The jetting and/or firing techniques introduced above can be implemented by programmable circuitry programmed/configured by software and/or firmware, or entirely by special-purpose circuitry, or by a combination of such forms. Such special-purpose circuitry (if any) can be in the form of, for example, one or more application-specific integrated circuits (ASICs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), etc.

Software or firmware to implement the techniques introduced here may be stored on a machine-readable storage medium and may be executed by one or more general-purpose or special-purpose programmable microprocessors. A “machine-readable medium”, as the term is used herein, includes any mechanism that can store information in a form accessible by a machine (a machine may be, for example, a computer, network device, cellular phone, personal digital assistant (PDA), manufacturing tool, or any device with one or more processors, etc.). For example, a machine-accessible medium includes recordable/non-recordable media, e.g., read-only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; etc.

Note that any and all of the embodiments described above can be combined with each other, except to the extent that it may be stated otherwise above or to the extent that any such embodiments might be mutually exclusive in function and/or structure.

Although the present invention has been described with reference to specific exemplary embodiments, it will be recognized that the invention is not limited to the embodiments described, but can be practiced with modification and alteration within the spirit and scope of the appended claims. Accordingly, the specification and drawings are to be regarded in an illustrative sense rather than a restrictive sense. 

What is claimed is:
 1. A composition comprising: a pigment compound configured to be jetted on a ceramic substrate during a ceramic inkjet process to impart a color effect to the ceramic substrate; and a reduction agent which, when exposed to a firing temperature, reacts with the pigment compound to cause a reduction reaction.
 2. The composition of claim 1, wherein the pigment compound comprises copper.
 3. The composition of claim 2, wherein the copper comprises particles having a particle size of less than 1 micron.
 4. The composition of claim 2, wherein the copper comprises any of CuO, CuCO₃, or CuS0₄.
 5. The composition of claim 1, wherein the reduction agent comprises any of Si0, SiC, SiN, or BN.
 6. The composition of claim 1, wherein the reduction reaction results in the composition taking on a color.
 7. The composition of claim 6, wherein the color extends a characteristic color gamut for the composition.
 8. The composition of claim 1, wherein the reduction reaction results in the composition taking on a red color having a characteristic wavelength of 620-740 nm upon firing.
 9. The composition of claim 1, wherein the reduction reaction results in the composition taking on any of a violet, burgundy, or oxblood color having a characteristic wavelength of 380-440 nm upon firing.
 10. The composition of claim 1, wherein the pigment compound is configured to be jetted onto the ceramic substrate, and wherein the reduction agent is configured to be jetted onto the pigment compound.
 11. The composition of claim 1, wherein the reduction agent is configured to be jetted onto the ceramic substrate, and wherein the pigment compound is configured to be jetted onto the jetted reduction agent.
 12. The composition of claim 1, wherein the pigment compound and the reduction agent are configured to be jetted concurrently onto the ceramic substrate.
 13. The composition of claim 1, further comprising a carrier.
 14. The composition of claim 1, further comprising any of a pigment, a dye, or a colorant.
 15. The composition of claim 1, wherein the firing temperature has a range of 1050 degrees C. to 1300 degrees C.
 16. A method comprising: jetting a composition onto a ceramic substrate, wherein the composition includes a pigment and a reduction agent; and causing a color effect to be produced on the ceramic substrate by heating the composition to a temperature at which the reduction agent causes a reduction reaction with the pigment.
 17. The method of claim 16, wherein the temperature has a range of 1050 degrees C. to 1300 degrees C.
 18. The method of claim 16, wherein the pigment comprises copper.
 19. The method of claim 17, wherein the copper comprises any of CuO, CuCO₃, or CuS0₄.
 20. The method of claim 16, wherein the pigment comprises particles having a particle size of less than 1 micron.
 21. The method of claim 16, wherein the reduction agent comprises any of Si0, SiC, SiN, or BN.
 22. The method of claim 16, wherein the jetting comprises: jetting the pigment onto the ceramic substrate; and jetting the reduction agent onto the jetted pigment.
 23. The method of claim 16, wherein the jetting comprises: jetting the reduction agent onto the ceramic substrate; and jetting the pigment onto the reduction agent.
 24. The method of claim 16, wherein the jetting comprises: concurrently jetting the pigment and the reduction agent onto the ceramic substrate.
 25. A printing system, comprising: a print head assembly to jet a composition onto a ceramic substrate, wherein the inkjet ink includes a pigment compound configured to impart a color effect to the ceramic substrate, and a reduction agent which, when exposed to a firing temperature, reacts with the pigment compound to cause a reduction reaction.
 26. The printing system of claim 25, wherein the printing assembly comprises a first print head for jetting the pigment compound, and a second print head for jetting the reduction agent.
 27. The printing system of claim 25, wherein the print head assembly is configured to be concurrently jet the pigment compound and the reduction agent onto the ceramic substrate.
 28. A method for manufacturing a composition for jetting onto a ceramic substrate, the method comprising: adding one of a jettable pigment compound or a jettable reduction agent to a liquid carrier; and adding the other of the jettable pigment compound or a the jettable reduction agent to the liquid carrier; wherein the jettable reduction agent is configured to react with the jettable pigment compound, when exposed to a firing temperature, to cause a reduction reaction and impart a color effect to the ceramic substrate.
 29. The method of claim 28, wherein the jettable pigment compound comprises copper particles.
 30. The method of claim 28, wherein the jettable pigment compound comprises particles having a size of less than 1 micron. 